Which of the following sentences uses a coordinating conjunction in a compound sentence? a. the budget payment is much higher than we anticipated, but the price of heating oil has skyrocketed this year. b. out in the yard, the children shouted loudly and threw silly insults at each other. c. my aunt, who usually behaves like a queen, was suddenly asking—no, begging—for . d. we fired our old housekeeper, who we thought had stolen grandma's rings; we later regretted it.